stuff about crystal well?

No, the performance of your IGP will have no effect at all on the performance of your GTX 780 Ti.
Unless you are using the IGP to run additional displays, it will remain completely unutilized when gaming.
The only time you are ever likely to use the IGP is encoding/decoding videos with Quick Sync.

Aside from that, Intel fastest desktop offering is the HD 4600.
The HD 5000, Iris 5100 and Iris Pro 5200 IGPs are only available in laptops and all-in-one desktops.